1. Field of the Invention
The present invention relates to an image forming apparatus of an electrophotographic system or the like.
2. Description of the Related Art
In an image forming apparatus of an electrophotographic system, a toner image is transferred to a sheet, and this toner image is fixed to the sheet. With respect to the fixation of the toner image, a heat pressure fixing device using heat and pressure is generally used. There is a fear that radiation heat or the like generated from this kind of fixing device has a bad influence on other structural elements.
Thus, it is conventionally well known to provide a blowing unit for exhausting the heat of the fixing device to the outside (see patent documents 1 to 3).                [Patent document 1] JP-A-2-50169        [Patent document 2] JP-A-5-224476        [Patent document 3] JP-A-6-230617        
However, when an image forming apparatus is miniaturized, respective structural elements must be put together and arranged, and there is increased fear that the heat generated from the fixing device has a bad influence on other structural elements. Especially, when the heat enters an exposure part, the temperature of a component (for example, a plastic lens or a scanner motor) constituting the exposure part becomes high, and there is a problem that the refractivity is changed by the thermal expansion of the plastic lens, or the lifetime of bearings of the scanner motor becomes short. Besides, when a cooling unit is provided in the respective structural elements, the number of parts is increased, and this causes the cost to become high and may hinder the miniaturization of the image forming apparatus.